greylisting and backup smart host

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Posts: 11
Joined: Sun Jul 22, 2007 11:33 am

greylisting and backup smart host

Post by » Thu May 29, 2008 2:47 pm

Hi, we have the following setup:

A primary mailenable server, and a backup mail server that smart hosts email back to these primary servers. mx record priority 10 points to the primary server and mx record priority 20 to the backup. Greylisting is enabled on all servers.

This all seems to work fine, however even though the primary is up 99% of the time email traffic seems to find itself to the backup (mx record prioty 20) quite regularly (then to be smart hosted back to the primary). again this in theory is ok, except for the following situation potentially:

if on occassion an email is routed to the backup server (via mx record 20) and then greylisted, does the sending email server know to retry to the same mx record / server or will it default back to the primary mx record if its available? if this happens then the greylisting will not be passed.

how that makes sense. any help / info appreciated.

Posts: 316
Joined: Mon Jan 19, 2004 5:00 pm
Location: Marion, IN

Post by dreniarb » Wed Jun 11, 2008 9:57 pm

i think it all depends on the sending mail server software.

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